Storage System Having Cross Node Data Redundancy and Method and Computer Readable Medium for Same

1. A method, comprising: forming a first level disk array from first level disk drives of a plurality of disk drives of a node of a plurality of nodes; forming a second level disk array from second level disk drives of the plurality of disk drives of the node; forming a third level disk array by subdividing the second level disk array into a plurality of third level disk drives; making the third level disks drives available for providing data redundancy across a geographical site; and rebuilding only a portion of the second disk array corresponding to a certain bit of a bitmap corresponding to a location on a particular disk.

2. The method of claim 1 , further comprising: providing data redundancy across the plurality of disk drives, wherein the data redundancy comprises one of a RAID5 architecture and a RAID6 architecture.

3. The method of claim 1 , wherein a data layout across the first level disk array comprises a RAID0 architecture.

4. The method of claim 1 , wherein the forming the second level disk array further comprises: subdividing the first level disk array of the node into the second level disk drives.

5. The method of claim 1 , further comprising: restoring data using the second level disk array responsive to failure of the node.

6. The method of claim 1 , wherein the failure of the node includes temporary unavailability of the node.

7. The method of claim 1 , further comprising: receiving an indication of an additional node having additional disk drives; scanning the second level disk array to identify selected second level disk drives of the second level disk array for migration; and migrating the selected disk drives to the additional node using online mirroring and copying.

8. The method of claim 7 , wherein the second level disk array has a width, and wherein the method further comprises: generating another second level disk array having a width larger than a width of the second level disk array.

9. The method of claim 1 , wherein the forming the second level disk array further comprises: forming the second level disk array both the second level disk drives of the node and a second plurality of disk drives from another node of the plurality of nodes.

10. The method of claim 1 , further comprising: receiving an indication that the particular disk has been restored.

11. A non-transitory computer readable medium comprising instructions that when executed by a processor cause the processor to perform: forming a first level disk array from first level disk drives of a plurality of disk drives of a node of a plurality of nodes; forming a second level disk array from second level disk drives of the plurality of disk drives of the node; forming a third level disk array by subdividing the second level disk array into a plurality of third level disk drives; making the third level disks drives available for providing data redundancy across a geographical site; and rebuilding only a portion of the second disk array corresponding to a certain bit of a bitmap corresponding to a location on a particular disk.

12. The non-transitory computer readable medium of claim 11 , wherein the instructions further cause the processor to perform: providing data redundancy across the plurality of disk drives, wherein the data redundancy comprises one of a RAID5 architecture and a RAID6 architecture.

13. The non-transitory computer readable medium of claim 11 , wherein a data layout across the first level disk array comprises a RAID0 architecture.

14. The non-transitory computer readable medium of claim 11 , wherein the forming the second level disk array further comprises: instructions the processor perform subdividing the first level disk array of the node into the second level disk drives.

15. The non-transitory computer readable medium of claim 11 , wherein the instructions further cause the processor to perform: restoring data using the second level disk array responsive to failure of the node.

16. The non-transitory computer readable medium of claim 15 , wherein the failure of the node includes temporary unavailability of the node.

17. The non-transitory computer readable medium of claim 11 , wherein the instructions further cause the processor to perform: receiving an indication of an additional node having additional disk drives; scanning the second level disk array to identify selected second level disk drives of the second level disk array for migration; and migrating the selected disk drives to the additional node using online mirroring and copying.

18. The non-transitory computer readable medium of claim 11 , wherein the second level disk array has a width, and wherein the method further comprises: generating another second level disk array having a width larger than a width of the second level disk array.